Nudge theory (or nudge) is a concept in behavioural science, political theory and economics which proposes positive reinforcement and indirect suggestions to try to achieve non-forced compliance to influence the motives, incentives and decision making of groups and individuals. The theory claims to be at least as effective, if not more effective, than direct instruction, legislation, or enforcement. The concept has influenced British and American politicians.
At the heart of nudge theory is the concept of nudge. The first formulation of this term and associated principles was developed in cybernetics by James Wilk before 1995 and described by Brunel University academic D. J. Stewart as "the art of the nudge" (sometimes referred to as micronudges). It also drew on methodological influences from clinical psychotherapy tracing back to Gregory Bateson, including contributions from Milton Erickson, Watzlawick, Weakland and Fisch, and Bill O'Hanlon. In this variant, the nudge is a microtargetted design geared towards a specific group of people, irrespective of the scale of intended intervention.
In 2008, Richard Thaler and Cass Sunstein's book Nudge: Improving Decisions About Health, Wealth, and Happiness brought nudge theory to prominence. The volume brought the discourse on nudge theory to the wider public. It also gained a following among US and UK politicians, in the private sector and in public health. The authors refer to influencing behaviour without coercion as libertarian paternalism and the influencers as choice architects. Thaler and Sunstein defined their concept as: